Evaluation method of diagnostic function for a variable valve mechanism and evaluation apparatus for a variable valve mechanism

Abstract

Evaluation of a diagnosis function for diagnosing a transient response of a variable valve mechanism for an engine valve is executed in a manner such that a desired value on the variable valve mechanism is calculated based on testing signals of a rotating speed and a water temperature, that a controlled variable signal for testing indicating a state in which the transient response of the variable valve mechanism is delayed, is generated, and that the diagnostic function for the transient response is evaluated based on whether or not the delay of the transient response is diagnosed on the basis of a correlation between the desired value and a controlled variable signal.

1. A method of evaluating a diagnostic function to diagnose a transient response of a variable valve mechanism, which varies operating characteristics of an engine valve, comprising the steps of:
 generating a test signal for reproducing a state in which the transient response of the variable valve mechanism is delayed; 
 executing the diagnosing function for diagnosing the transient response of the variable valve mechanism in the state of the delayed transient response of the variable valve mechanism, which is reproduced based on the test signal; and 
 evaluating the diagnostic function of the transient response based on a result of the execution of the diagnosing function. 
 
   
   
     2. The evaluating method according to  claim 1 , wherein
 the step of generating the test signal comprises the step of generating, as the test signal, a controlled variable signal indicative of a controlled variable of the variable valve mechanism, and wherein 
 the step of executing the diagnosing function for diagnosing the transient response comprises the step of diagnosing the transient response of the variable valve mechanism based on the generated controlled variable signal for testing and a desired value. 
 
   
   
     3. The evaluating method according to  claim 1 , wherein the step of generating the test signal comprises the step of generating, as the test signal, a position signal indicative of a position of a controlled system of the variable valve mechanism, and
 wherein the step of executing the diagnosing function for diagnosing the transient response comprises the step of diagnosing the transient response of the variable valve mechanism based on the generated position signal for testing and a desired value. 
 
   
   
     4. The evaluating method according to  claim 2 , wherein the step of generating the test signal comprises the step of generating, as the test signal, the controlled variable signal as well as an operation condition signal which indicates an operation condition of an internal combustion engine, and
 wherein the step of executing the diagnosing function for diagnosing the transient response comprises the step of diagnosing the transient response of the variable valve mechanism based on a desired value which is set on the basis of the testing operation condition signal and the testing controlled variable signal. 
 
   
   
     5. The evaluating method according to  claim 4 , wherein the step of generating the test signal comprises the step of generating an engine rotating speed signal as the operation condition signal for testing. 
   
   
     6. The evaluating method according to  claim 4 , wherein the step of generating the test signal comprises the step of generating a cooling water temperature signal as the operation condition signal for testing. 
   
   
     7. The evaluating method according to  claim 2 , wherein the step of executing the diagnosing function for diagnosing the transient response includes the steps of measuring a time required for the controlled variable signal for testing to be converged into a desired value, and diagnosing the transient response of the variable valve mechanism based on the time. 
   
   
     8. The evaluating method according to  claim 2 , wherein the step of executing the diagnosing function for diagnosing the transient response includes the steps of:
 calculating a deviation between the controlled variable signal for testing and a desired value; 
 measuring a time during which a state in which the deviation is equal to or more than a predetermined value continues; and 
 diagnosing the transient response of the variable valve mechanism based on the measured time. 
 
   
   
     9. The evaluating method according to  claim 1 , wherein the step of evaluating the diagnostic function determines that the diagnostic function for diagnosing the transient response is abnormal when the transient response of the variable valve mechanism is diagnosed as being normal by the execution of the diagnosing function for the transient response. 
   
   
     10. The evaluating method according to  claim 1 , wherein the step of generating the test signal is executed by an external checker arranged to be connected to a control unit of the variable valve mechanism, and
 wherein the step of executing the diagnosing function for diagnosing the transient response is executed by the control unit arranged to receive a test signal generated by the checker. 
 
   
   
     11. The evaluating method according to  claim 10 , wherein the step of executing the diagnosing function for diagnosing the transient response is executed by the control apparatus of the variable valve mechanism, the control unit outputting a signal indicative of a result of diagnosis to the external checker. 
   
   
     12. An evaluation apparatus for evaluating diagnosing function for diagnosing a transient response of a variable valve mechanism adapted for changing operating characteristics of an engine valve; comprising:
 a signal generator that generates a test signal for reproducing a state in which the transient response of the variable valve mechanism is delayed; 
 a diagnosing unit that has a function to diagnose the transient response of the variable valve mechanism in the state of the delayed transient response of the variable valve mechanism, which is reproduced based on the test signal; and 
 an evaluating unit that evaluates the function of diagnosing the transient response of the variable valve mechanism based on a result of the diagnosis by the diagnosing unit. 
 
   
   
     13. The evaluation apparatus according to  claim 12 , wherein the signal generator generates, as the test signal, a controlled variable signal indicative of a controlled variable of the variable valve mechanism, and
 wherein the diagnosing unit diagnoses the transient response of the variable valve mechanism based on the controlled variable signal for testing and a desired value. 
 
   
   
     14. The evaluation apparatus according to  claim 12 , wherein the signal generator generates, as the test signal, a position signal indicative of a position of a controlled system of the variable valve mechanism, and
 wherein the diagnosing unit diagnoses the transient response of the variable valve mechanism based on the testing position signal and a desired value. 
 
   
   
     15. The evaluation apparatus according to  claim 13 , wherein the signal generator generates, as the test signal, the controlled variable signal as well as an operation condition signal indicative of an operation condition of an internal combustion engine, and
 wherein the diagnosing unit diagnoses the transient response of the variable valve mechanism based on a desired value which is set on the basis of the operation condition signal for testing and the controlled variable signal for testing. 
 
   
   
     16. The evaluation apparatus according to  claim 15 , wherein the signal generator generates an engine rotating speed signal as the testing operation condition signal. 
   
   
     17. The evaluation apparatus according to  claim 15 , wherein the signal generator generates a cooling water temperature signal as the operation condition signal for testing. 
   
   
     18. The evaluation apparatus according to  claim 13 , wherein the diagnosing unit measures a time required for the control variable signal for testing to be converged into a desired value, and diagnoses the transient response of the variable valve mechanism based on the measured time. 
   
   
     19. The evaluation apparatus according to  claim 13 , wherein the diagnosing unit measures a time during which a state in which a deviation between the control variable signal for testing and the desired value is equal to or larger than a predetermined value continues, and diagnoses the transient response of the variable valve mechanism based on the measured time. 
   
   
     20. The evaluation apparatus according to  claim 12 , wherein the evaluation unit determines that the function to diagnose the transient response of the variable valve mechanism is abnormal when the transient response of the variable valve mechanism is diagnosed as being normal as a result of the diagnosis of the transient response. 
   
   
     21. The evaluation apparatus according to  claim 12 , wherein the signal generator is provided in an external checker, which is connected to a control unit of the variable valve mechanism, the control unit receiving a test signal generated by the checker. 
   
   
     22. The evaluation apparatus according to  claim 12 , wherein the diagnosing unit is provided in a control unit of the variable valve mechanism, the control unit outputting a signal indicative of a result of diagnosis to an external checker.